This invention relates to a holder for receiving loose optical fibers.
Optical fibers that are currently commercially available comprise a central glass core, a glass cladding that surrounds the core, and a coating of synthetic polymer material. Typically, the external diameter of the cladding is about 125 .mu.m and the external diameter of the polymer coating is approximately 250 .mu.m.
In some markets, optical fiber is used mainly in ribbon form, whereas in other markets it is more common to use optical fiber in the form of individual loose fibers. In ribbon fiber, the individual component fibers are bonded together in approximately parallel side-by side relationship, such that in any perpendicular cross section through the ribbon fiber, the points at which the central axes of the individual component fibers pass through the plane of the section lie approximately on a straight line.
U.S. Pat. No. 5,375,179, the disclosure of which is hereby incorporated by reference herein, discloses a test instrument in which an end segment of a ribbon fiber is held in a ribbon fiber clamp or holder. A practical implementation of that instrument, sold by Photon Kinetics, Inc. as its OASYS 1000 instrument, includes a carriage that is provided with locating features for receiving the ribbon fiber holder. The ribbon fiber holder may be, for example, the holder that is sold by Photon Kinetics as option 1000-B12 for the OASYS 1000 instrument.
In order to test an optical fiber, it is generally necessary to prepare the fiber by stripping the polymer coating from an end segment of the fiber and cleaving the stripped fiber end segment. A ribbon fiber having an end segment that is held in the Photon Kinetics 1000-B12 ribbon fiber holder may be prepared for testing using the Photon Kinetics 1000-RST ribbon fiber stripper for stripping the polymer coating and the Photon Kinetics 1000-RCL ribbon fiber cleaver for cleaving the stripped ribbon fiber end segment. These fiber preparation devices are specifically designed for use with fibers that are in ribbon form.
Hitherto, in order to use a ribbon fiber test instrument, such as the Photon Kinetics OASYS 1000 instrument, for testing loose fibers, it has been necessary to ribbonize the fibers by holding them in a clamping device and applying some form of adhesive to the fibers. When the fibers have been ribbonized in this manner, the fibers can be prepared for testing by stripping and cleaving.
It is inconvenient and time consuming to ribbonize loose fibers in the manner described above. Moreover, the coatings used for ribbon fiber are generally designed so that the coating can be stripped from all the component fibers at once, often in one piece, whereas loose fibers are intended to be stripped singly. Consequently, the force required to strip several ribbonized loose fibers at one time is considerably greater than that needed to strip a ribbon fiber composed of a comparable number of individual fibers. Therefore, even when the loose fibers have been ribbonized, it is more difficult to use the same ribbon fiber holder and hot jacket stripper as are used for ribbon fibers to hold and strip the ribbonized fibers, because the holder does not grip the fibers firmly enough to allow sufficient stripping force to be applied.